Section 5: Pediatrics

Question 1

Normal vital signs in the newborn

• Respiratory rate (RR)
• Heart rate (HR)

Answer 1

• RR: 40 to 60 breaths per minute
• HR: 120 to 160 beats per minute

Question 2

A 28-year-old G₁ P₀ woman delivers a 3.9 kg male infant whose Apgar scores are 9 and 10 at 1 and 5 minutes respectively. The delivery was uncomplicated and both mother and child are in no acute distress. What is the most appropriate next step in management of this patient?

a. Intubate the child
b. Send cord blood for arterial blood gas (ABG)
c. Suction the mouth and nose
d. Nasogastric tube (NGT) placement
e. Give prophylactic antibiotics

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 403). Kaplan Medical Test Prep. Kindle Edition.

Answer 2

C. Once the child is delivered, the mouth and nose are suctioned, followed by clamping and cutting of the umbilical cord. The newborn is then dried, wrapped
in clean towels, and placed under a warmer as he has just descended from an environment of 98.6° F to approximately 65° F. Gentle rubbing or stimulating the heels of the newborn helps to stimulate crying and breathing. Intubation and ABG analysis of the
child are indicated only if the newborn is not breathing or is in respiratory distress. Nasogastric tube placement is indicated when GI decompression is needed. Antibiotics are indicated for sepsis.

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 403). Kaplan Medical Test Prep. Kindle Edition.

Question 3

Outline the Rx given at delivery of the newborn

Answer 3

• 1% silver nitrate eye drops or 0.5% erythromycin ophthalmic ointment
• 1mg of vitamin K IM to prevent vitamin K deficient bleeding (VKDB). VKDB used to be known as hemorrhagic disease of the newborn

Question 4

List screening tests to do before discharge

Answer 4

1. Hearing test to rule out sensorineural hearing loss
2. Phenylketonuria
3. Galactosemia
4. Hypothyroidism

Question 5

Apgar Score

The Apgar score delineates a quantifiable measurement for the need and effectiveness of resuscitation. The Apgar score does not predict mortality.

• What does the one-minute Apgar score evaluate?
• What does the five-minute Apgar score evaluate?

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 404). Kaplan Medical Test Prep. Kindle Edition.

Answer 5

• One-minute score evaluates conditions during labor and delivery
• Five-minute score evaluates the response to resuscitative efforts.

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 404). Kaplan Medical Test Prep. Kindle Edition.

Question 6

True or False:

A low score on the Apgar is associated with future cerebral palsy.

Answer 6

False

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 404). Kaplan Medical Test Prep. Kindle Edition.

Question 7

A 3.9 kg male infant whose Apgar scores were 9 and 10 at 1 and 5 minutes, respectively, after delivery is brought in by his parents because his eyes are red.
The delivery was without any complications and both mother and child are in no acute distress. What is the most likely diagnosis at 1 day, at 2 to 7 days, and at >7 days?
a. Chemical irritation
b. Neisseria gonorrhoeae
c. Chlamydia trachomatis
d. Herpes simplex
e. All of the above

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 404). Kaplan Medical Test Prep. Kindle Edition.

Answer 7

E. To diagnose the cause of conjunctivitis in the newborn, you must consider when the redness and irritation begins.

• At 1 day, the most likely cause of the conjunctivitis is chemical irritation
• From days 2 to 7, the most likely cause is Neisseria gonorrhoeae
• Conjunctivitis after more than 7 days post delivery is most likely due to Chlamydia trachomatis
• Conjunctivitis after 3 weeks or more is most likely due to herpes infection.

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 404). Kaplan Medical Test Prep. Kindle Edition.

Question 8

List the criteria of the Apgar Score

Answer 8

Acronym used is APGAR

1. Appearance = Skin color/complexion
   
   • Blue all over = 0
   • Normal except extremities = 1
   • Normal all over = 2
2. Pulse = Pulse rate
   
   • < 60 bpm or asystole = 0
   • > 60 bpm but < 100 bpm = 1
   • > 100 bpm = 2
3. Grimace = Reflex irritability
   
   • No response = 0
   • Grimace/feeble cry = 1
   • Sneeze/cough = 2
4. Activity = Muscle tone
   
   • None = 0
   • Some flexion = 1
   • Active movement = 2
5. Respiration = Breathing
   
   • Absent = 0
   • Weak or irregular = 1
   • Strong = 2

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 404). Kaplan Medical Test Prep. Kindle Edition.

Question 9

List the lab abnormalities of infant of a diabetic mother (IODM)

Answer 9

• Hypoglycemia
• Hypocalcemia
• Hypomagnesemia
• Hyperbilirubinemia
• Polycythemia

Question 10

List the congenital abnormalities associated with IODM

Answer 10

• Cardiac abnormalities (ASD, VSD, truncus arteriosus)
• Small left colon syndrome

Question 11

True or False:

IODM is associated with an increased risk of developing diabetes and childhood obesity

Answer 11

True

Question 12

A 1-week-old newborn is brought to the ED after a home delivery. His parents state they do not believe in vaccinations nor did they seek any medical attention
after delivery. They state they have noticed bright red blood per rectum from the infant and he is very lethargic. On examination the infant has unequal pupils and his diaper has gross red blood. What is the most likely diagnosis?
a. Cerebrovascular accident
b. Meckel’s diverticulum
c. Vitamin K deficient bleeding
d. Crohn disease

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 405). Kaplan Medical Test Prep. Kindle Edition.

Answer 12

C. As this child received no routine newborn care, it is very likely he is suffering from a vitamin K deficiency. Newborns are at most risk as their immature livers do not utilize vitamin K to develop the appropriate clotting factors. Breast milk typically has very low levels of vitamin K. The child’s lethargy is likely from intracranial bleeding, and the bright red blood per rectum is mucosal bleeding. The child’s age precludes a diagnosis of CVA, Crohn disease, or a Meckel’s diverticulum.

Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 405). Kaplan Medical Test Prep. Kindle Edition.

Question 13

Respiratory distress in the newborn

1. Best initial test
2. List the other diagnostic studies
3. Best initial Rx

Answer 13

1. Chest X-ray
2. Other tests:
   
   • ABG
   • Blood cultures (R/O sepsis)
   • Blood glucose (R/O hypoglycemia)
   • CBC (R/O anemia or polycythemia)
   • Cranial ultrasound (R/O intracranial hemorrhage)
3. Best initial Rx:
   
   • Oxygen: keep SaO₂ > 95%
   • Give nasal CPAP if high O₂ requirements to prevent barotrauma and bronchopulmonary dysplasia
   • Consider empiric antibiotics for suspected sepsis

Question 14

Meconium aspiration 1:

List the diagnostic test and the findings

Answer 14

CXR. Findings are;

• Patchy infiltrates
• Increased AP diameter (barrel chest)
• Flattening of the diaphragm

Question 15

Rx of meconium aspiration

Answer 15

• positive pressure ventillation
• High-frequency ventillation
• Nitric oxide therapy
• Extracorporeal membrane oxygenation

Question 16

How to prevent meconium aspiration?

Answer 16

endotracheal intubation and airway suction of depressed infants

Question 17

Possible complications of meconium aspiration

Answer 17

• Pulmonary artery HTN
• Air leak (pneumothorax, pneumomediastinum)
• Aspiration pneumonitis

Question 18

Meconium plugs are seen in the lower colon. List the conditions associated with meconium plugs

Answer 18

• Small left colon in IODM
• Hirschsprung disease
• Cystic fibrosis
• Maternal drug abuse

Question 19

Meconium ileus is seen in the lower ileum. List the condition in which it is associated with.

Answer 19

Cystic fibrosis

Question 20

Best initial diagnostic test and Rx of meconium plug and ileus

Answer 20

Best initial test: Abdominal X-ray

Rx: Gastrografin enema

Question 21

List the components of the VACTERL syndrome

Answer 21

• Vertebral defects
• Anal atresia
• Cardiac abnormalities
• Tracheoesophageal fistula with esophageal atresia
• Radial and Renal anomalies
• Limb syndrome

Question 22

A premature infant is born by normal vaginal delivery without complication. There is no respiratory distress. Upon the first feed, she begins vomiting gastric and bilious material. CXR is shown. What is the most likely diagnosis?

Answer 22

Duodenal atresia. Half of infants with this condition are born prematurely, and the condition is associated with Down syndrome. Look for polyhydramnios in the prenatal exam. Treatment involves NG decompression and surgical correction. You must search for other abnormalities (VACTERL association) with X-ray of the spine, abdominal ultrasound, and echocardiogram

Question 23

List the differential diagnosis of double-bubble seen on abdominal X-ray of newborn infants

Answer 23

• Duodenal atresia
• Annular pancreas
• Malroration
• Volvulus

Question 24

When is hyperbilirubinemia considered pathological?

Answer 24

• It appears on the first day of life
• Bilirubin rises > 5mg/dL/day
• Bilirubin > 12mg/dL in term infant
• Direct bilirubin > 2mg/dL at any time
• Hyperbilirubinemia is present after the 2nd week of life

Question 25

List the causes of direct bilirubinemia

Answer 25

* Sepsis * TORCH infections * Total parenteral nutrition * Hypothyroid * Galactosemia * Tyrosinemia * Cystic fibrosis * Choledochal cyst

Question 26

List the causes of a Coombs positive indirect hyperbilirubinemia

Answer 26

* Rh incompatibility * ABO incompatibility * Thalassemia minor

Question 27

List the causes of a Coombs negative indirect hyperbilirubinemia with high hgb

Answer 27

* Polycythemia * Twin-twin transfusion * Maternal-fetal transfusion * Delayed cord * IURG * Infant of diabetic mother

Question 28

List the diagnostic work-up for jaundice presenting in the first 24 hours

Answer 28

* Total and direct bilirubin * Blood type of infant and mother: Look for ABO or Rh incompatibility * Direct Coomb's test * CBC, reticulocyte count, and smear: Assess for hemolysis * Urinalysis and culture if elevated direct bilirubin: Assess for sepsis

Question 29

List the common causes (organisms) of early onset neonatal sepsis

Answer 29

Group B Streptococcus E. coli Haemophilus influenzae Listeria monocytogenes

Question 30

List the common causes of late onset neonatal sepsis

Answer 30

Staphylococcus aureus E.coli Klebsiella Pseudomoans

Question 31

In the newborn intensive care unit, an infant is noted to be "jittery" and has repetitive sucking movements, tongue thrusting, and brief apneic spells. Blood counts and chemistries are within normal limits. What is the initial workup of this patient?

Answer 31

Seizures classically pesent with subtle repetitive movements, such as chewing, tongue thrusting, apnea, staring, blinking, or desaturations. Classic-tonic clonic movements are uncommon. Look for ocular deviation and failure of jitteriness to subside with stimulus (e.g., passive movement of a limb)

Question 32

List the diagnostic tests in neonatal seizures

Answer 32

EEG: may be normal CBC, electrolytes, calcium, magnesium, phosphorous, glucose Amino acid assay and urine organic acids Total cord blood IgM for TORCH infection studies Blood and urine cultures LP if meningitis is suspected Ultrasound of the head in preterms for intraventricular hemorrhage

Question 33

Best initial Rx of neonatal seizure Rx if seizure persists

Answer 33

Phenobarbital Phenytoin

Question 34

List the CF of neonatal withdrawal to substance abuse

Answer 34

* Hyperactivity * Irritability * Fever * Diarrhea * Tremors/jitters * High-pitched crying * Sneezing * Restlessness * Vomiting * Nasal suffiness * Poor feeding * Seizures * Tachypnea

Question 35

If the infant presents with substance withdrawal symptoms **within the first 48 hours**, list the likely abused substances

Answer 35

* Heroin * Cocaine * Amphetamine * Alcohol

Question 36

True or False: 1. Methadone is associated with a higher risk of seizures 2. Methadone withdrawal presents within the first 48 hours 3. Methadone withdrawal may present up to 2 weeks

Answer 36

1. True 2. False. It is within the first 96 hours 3. True

Question 37

List the complications of infants of addicted mothers are at higher risk of

Answer 37

Low birth weight Intrauterine growth retardation (IURG) Congenital anomalies (alcohol, cocaine) Sudden infant death syndrome (SIDS)

Question 38

Best initial Rx for neonatal withdrawal to mother's substance abuse

Answer 38

**Opioids** (especially if specific opioid use was known) and **Phenobarbital**

Question 39

True or False: Never give naloxone to an infant born from mother with known narcotics use. Why?

Answer 39

True. It may precipitate sudden withdrawal, including seizures

Question 40

A premature infant born at 28 weeks is in respiratory distress, with grunting, nasal flaring, and the use of accessory muscles. Bowel sounds are heard upon auscultation of the back and chest x-ray shows air fluid levels are seen in the chest. Which of the following is the most likely diagnosis? a. Hydrocele b. Gastroschisis c. Diaphragmatic hernia d. Hiatal hernia e. Omphalocele Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 409). Kaplan Medical Test Prep. Kindle Edition.

Answer 40

**C**. A hernia in the diaphragm will allow for bowel contents to move into the chest and impair ventilation. Hydrocele is a urinary defect and is not seen on x-ray. It cannot be gastroschisis or omphalocele, as those are defined as an extrusion of abdominal contents outside of the body. Hiatal hernia is a benign finding most commonly seen in elderly or obese patients. Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 409). Kaplan Medical Test Prep. Kindle Edition.

Question 41

Upon her first feeding, a 1-day-old child begins to choke and exhales milk bubbles from her nose, then appears to be in significant respiratory distress. CXR reveals an air bubble in the upper esophagus and no gas pattern in the remainder of the GI tract. A coiled NGT is also seen. What is the most common complication of this condition? a. Meningitis b. Pneumonia c. Dental caries d. Dyspepsia e. Belching Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 419). Kaplan Medical Test Prep. Kindle Edition.

Answer 41

**B**. The signs described both on physical exam and radiological exam point towards an esophageal atresia with a tracheoesophageal fistula. Aspiration pneumonia is a severe and common complication of this condition as food contents are aspirated via the fistula in the respiratory system. Aspiration leads to abscess formation from anaerobic proliferation. Dental caries cannot form because the child is only 1 day old and therefore does not have teeth. Food cannot reach the stomach, so there is no possibility for either dyspepsia or belching. Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 420). Kaplan Medical Test Prep. Kindle Edition.

Question 42

1-month-old child is fed, after which he has vomitus that is forceful and winds up across the nursery. The vomitus is nonbloody and nonbilious. Physical examination reveals a palpable mass in the abdomen. An upper GI series is ordered. Which of the following is the most likely finding on this radiologic exam? a. String sign b. Doughnut sign c. Bird’s beak sign d. Steeple sign e. Murphy sign Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 420). Kaplan Medical Test Prep. Kindle Edition.

Answer 42

A. Projectile vomiting and palpable abdominal mass is characteristic of pyloric stenosis. String sign is seen on upper GI series (barium is swallowed and its passage is watched under fluoroscopy). Doughnut sign is seen during intussusceptions. Bird’s beak is seen in achalasia, steeple sign is seen during croup, and the Murphy sign is not ever a radiological sign, but rather a physical exam sign with right upper quadrant tenderness that causes cessation of breathing. Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 421). Kaplan Medical Test Prep. Kindle Edition.

Question 43

1-day-old child is given her first feeding, at which time she begins to have very dark green vomiting. On physical examination, the child has oblique eye fissures with epicanthic skin folds and a single palmar crease. A holosystolic murmur is also heard. CXR reveals a double bubble sign. Which of the following is the most likely diagnosis? a. Biliary atresia b. Duodenal atresia c. Volvulus d. Intussusception e. Pyloric stenosis Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 424). Kaplan Medical Test Prep. Kindle Edition.

Answer 43

**B**. The child’s bilious vomiting on the first day of life is the prototypic finding in children with this condition. Furthermore, the description of Down syndrome-like characteristics such as eye shape, simian crease, and congenital murmur also points to duodenal atresia. Volvulus and intussusception would present with symptoms of obstruction such as distension and failure to pass flatus and stool, and do not have vomiting as a presenting symptom. Biliary atresia would not have any bilious Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 424). Kaplan Medical Test Prep. Kindle Edition.

Question 44

A 1-year-old child is having his diaper changed when his father notices the stool looks like a purple jelly. He quickly rushes to the ED and reports that the previous night, the child was very irritable, complained of pain, and had an episode of vomiting. On physical exam the child seems lethargic and a firm sausage-shaped mass is palpated. Which of the following is the most likely diagnosis? a. Biliary atresia b. Duodenal atresia c. Volvulus d. Intussusception e. Pyloric stenosis Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 425). Kaplan Medical Test Prep. Kindle Edition.

Answer 44

**D**. Intussusception presents with currant jelly stool, sausage-shaped mass, neurologic signs, and abdominal pains. The remaining choices do not fit this description. Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 425). Kaplan Medical Test Prep. Kindle Edition.

Question 45

An 11-month-old girl is brought from daycare to the ED for severe diarrhea and a fever of 103°F. The parents are still not present, but the daycare provider states that the girl has been lethargic, has not been eating, and has had several episodes of diarrhea. The last episode was bloody and contained mucus. Physical exam reveals a child who is listless and drowsy. Her skin shows signs of tenting. Laboratory findings show marked leuokocytosis, elevated BUN and creatinine, and markedly decreased bicarbonate and elevated hematocrit. Which of the following is the most appropriate next step in management of this patient? a. CT of the abdomen and pelvis b. Discharge home c. Fluid resuscitation d. Stool ova and parasite (O&P) analysis e. Empiric antibiotic delivery Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 427). Kaplan Medical Test Prep. Kindle Edition.

Answer 45

**C**. The child is severely dehydrated as demonstrated by acute renal failure secondary to hypovolemia, skin tenting, and hemoconcentration The most appropriate next step is aggressive IV fluid rehydration and electrolyte replenishment. At this time, no other test or therapy is important; this child is unstable and could be on the brink of hypovolemeic shock. Radiologic imaging delays the administration of fluids and discharging the child home could result in fatal consequences. Antibiotic coverage is not the most appropriate next step because antibiotics can take 12 to 24 hours to become effective. Antibiotics are needed, but fluids work faster and are needed more urgently at this time. Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 427). Kaplan Medical Test Prep. Kindle Edition.

Question 46

A 3-day-old preterm female neonate is noted by the resident to have increased gastric residual volume and abdominal distension. On rectal exam the stool is heme positive. Lactate is 2.9 mg/dL. A supine x-ray of the abdomen shows air in the bowel wall but no free air in the peritoneum. What is the best next step in management of this condition? A. Call surgical consult B. Start antibiotics C. CT scan of the abdomen D. 0.9% normal saline bolus E. Ringer lactate maintenance fluids Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 428). Kaplan Medical Test Prep. Kindle Edition.

Answer 46

**B**. When there is confirmed evidence of necrotizing enterocolitis, start antibiotics; the antibiotics of choice are vancomycin, gentamicin, and metronidazole. This is adjunct with serial abdominal x-rays to exclude perforation. Calling a consult is always the wrong answer on the USMLE, and a CT scan of the abdomen is not necessary, as x-ray can diagnose the findings. Although starting fluids is correct, it is not the best next step compared with initiating antimicrobial therapy. Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 428). Kaplan Medical Test Prep. Kindle Edition.

Question 47

A 10.5-pound infant is born to a mother with Type I diabetes. Upon examination of the newborn, he is shaking and a holosystolic murmur is heard over the precordium. The baby’s right arm is adducted and internally rotated. His lab findings show elevated bilirubin. Which of the following is the most appropriate next step in management? a. IV insulin b. Blood sugar level c. Serum calcium levels d. Serums TSH e. CT head and neck Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 429). Kaplan Medical Test Prep. Kindle Edition.

Answer 47

**B**. Infants of diabetic mothers (IDMs) are born macrosomic, with plethora, and can be very jittery. The newborn usually has dramatically high circulating levels of glucose, but upon delivery, maternal glucose is no longer available. This child is still producing high levels of insulin, and thus his blood sugar levels have dropped. Cardiac anomalies are common, as in this child, who most likely has a VSD. When we think of diabetes, our first thought is insulin treatment. This is the most common wrong answer, since it would further exacerbate these newborns’ problems. Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 429). Kaplan Medical Test Prep. Kindle Edition.

Question 48

A 6-month-old infant is brought in by his mother after what she describes as a seizure. The child has had a fever of 103°F for the last 3 days and has been very irritable lately. He appears unresponsive but is breathing. Physical examination reveals a markedly delayed capillary refill and a blood pressure of 80/20. What is the most likely diagnosis? a. Febrile seizure b. Absence seizure c. Dog bite d. Cocaine withdrawal e. Epilepsy Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 433). Kaplan Medical Test Prep. Kindle Edition.

Answer 48

**A**. This child has febrile seizure secondary to sepsis. The real take-home message with this case is to evaluate the child for the underlying cause of the sepsis. Understanding he has had a febrile seizure is only the surface of the case. A full sepsis evaluation must be ordered, which includes CBC with differential blood and urine cultures, urinalysis, chest x-ray, and lumbar puncture (if irritability or lethargy is mentioned = meningitis). Dog bites do not present with seizures. Cocaine withdrawal does not have seizures. Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 433). Kaplan Medical Test Prep. Kindle Edition.

Question 49

Neonatal Sepsis: 1. Most common causes 2. Most common organisms 3. Diagnostic tests 4. Rx

Answer 49

1. Pneumonia; Meningitis 2. Group B strep; E. coli; S. aureus; Listeria monocytogenes 3. Blood cultures and urine cultures; CXRay 4. Ampicillin and gentamicin Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 433). Kaplan Medical Test Prep. Kindle Edition.